Caloric piston engine comprising heat exchange devices



July 12, 1949. G. J. H. VERMEER 2,475,764

. CALORIC PISTON ENGINE COMPRISING HEAT EXCHANGE DEVICES Filed April 12,1946 s Sheets-Sheet 1 22 FIGJ FIG. 2

GERARD J. H. VERMEER iNVENTOR MMM7 AGENT G. J. H. VERMEER CALORIC PISTONENGINE COMPRISING July 12, 1949.

HEAT EXCHANGE DEVICES 5 Sheets-Sheet 2 Filed April 12, 1946 FIG. 6

FIG. 5

GERARD J. HNERMEER AGENT y 1949- G. J. H. VERMEER 2,475,764

CALORIC PISTON ENGINE COMPRISING v HEAT EXCHANGE DEVICES Filed April 12,1946 3 Sheets-Sheet 3 Ill k JIHI 1 1 11,111 11 r1111 11,, I I 1 GERARD JH VERMEER INVENTOR.

A GENT Patented July 12, 194 v CALORIC PISTON ENGINE COMPRISING HEATEXCHANGE DEVICES Gerard Jan Huber tus Vermeer, Eindhoven, Netherlands,assignor, b

Hartford National y mesne assignments, to Bank and Trust Company,

Hartford, Conn., as trustee Application April 12, 1946, Serial No.661,472 In the Netherlands December 6, 1945 7 Claims.

This invention relates to caloric piston machines (hot-gas enginerefrigerating apparatus operating on the reverse hot-gas engineprinciple) in which the working chamber is surrounded by an annularspace which compnses, owing to the presence of one or a plurality ofwalls, a number of spaces both for the working medium and for the mediumwhich is in heatexchanging contact with the working medium, which spacesare located in such manner that as viewed in a section normal to theaxis of the working space through the annular chamber, there are on anannular strip of this section spaces for the working medium as well asfor the medium which is in heat-exchanging contact with the former. Inorder to ensure a high output of such a machine, it is desirable thatthe heat-exchanging contact should be optimum. n the one hand, it isdesirable that the media should experience a minimum resistance in themachine on passing through the spaces intended for them. This can beensured by giving the paths along which the media move through theducts, a comparatively short length. Now, applicant has found that theserequirements can be fulfilled by using the present invention.

The caloric piston machine, according to the invention, has the featurethat the partitions between the two media are provided, on one or oneither side, with projecting parts such as ribs, fins or the like, sothat on at least one of the sides of these partitions the medium on thatside is compelled to flow, in a plurality of parallel paths, along thepartitions in one or more directions at an angle with the longitudinaldirection of the partitions.

By the subdivision of one or of the two media into a plurality ofparallel paths of flow it is ensured that this subdivided medium is in ahighly satisfactory heat-exchanging contact with the partitionconcerned. If, in addition, these flows are guided along the partitionsby the location of the projecting parts thereof in such a manner as tomake an angle with the longitudinal direction of the partitions, it is,moreover, ensured that the paths along which these flows pass along thepartitions in question are very short with the result that theresistance experienced b the medium concerned is low.

In one form of construction of the piston machine, according to theinvention, the ducts for the medium which is in heat-exchanging contactwith the working medium are formed by a plurality of tubes protrudinginto the annular space and externally provided with projecting parts.

2 It is advisable that these tubes, at least through the greater part oftheir length, should be slightly inclined with respect to the axis ofthe working space and this in such manner that the ends of the tubes inthe proximity of the machine lid are remotest from the axis of theworking space. In connection with the average direction of flow of themedium out of the engine space along the heat-exchanger to the remainingpart of the engine and conversely, it is thus ensured that the pathsalong which the working medium is in contact with the walls separatingthis medium from the medium with which the former is in heat-exchangingcontact, may have a short length. In addition, the heat-exchangingsurface available can be used more effectively than in the well-knownheat-exchanger.

In a further form of construction of the caloric piston machineaccording to the invention the spaces for the working medium and for themedium which is in heat-exchanging contact with the former are separatedby a screen which is folded zigzag and arranged in the annular space.

The projecting parts on the partitions between the two media may beobtained by locally embossing the material of the wall which ensures alight construction. As an alternative, the projecting parts may be madein a different manner. for example by milling grooves in the relativeportions of the wall, in which event the wall portions that have notbeen milled away form the projecting parts.

In a further form of construction of the piston machine according to theinvention the spaces for the medium which is in heat-exchanging contactwith the working medium comprises supply pipes for a combustible'gas,which pipes end in these spaces with a plurality of apertures, theprojecting parts being provided on the sides of the circumscribing wallsof these spaces which are facing these spaces, in such a manner as toform on these walls ducts for the flames leaving the gas outlets.

In order that the invention may be clearly understood and readilycarried into eifect, it will now be explained more fully by reference tothe accompanying drawings. a

Figure 1 is a diagrammatic sectional view of the head of a hot-gasengine.

Figure 2 is a longitudinal section of the head of a hot-gas engine inwhich a modified structure of the heat exchanger is shown.

Figure 3 is a transverse section of the modified heat exchanger alongthe line III-III in Figure 2.

Figure 4 is a longitudinal section of the modified heat exchanger alongthe line .IV--IV in heat exchanger shown in hot-gas engine in which athird form of the heat exchanger is shown.

is a horizontal cross sectional view in the drawing, may be slightlyinclined relatively to this axis. The latte form of construction therebyavoids too large a clearance space in the apparatus, and has the furtheradvantage that the ducts between the ribs l4 can, in general, be given asmaller length.

In a further form of construction or the machine according to theinvention, shown in Figures 2, 3 and 4 of which Figure 2 shows alongitudinal section of the head of a. hot-gas engine, Figure 3 is asectional view taken along the line IIIIII of Figure 2, and Figure 4 isa sectional the tubular heat exchanger shown in Figures 1 and '7.

Figure 9 is a horizontal cross sectional view of an alternateconstruction of the tubular heat exchanger shown in Figure 1.

Figm-e 1 is a diagrammatic sectional view of the head of a hot-gasengine as noted hereinabove. In it the displacer I is movable in acylinder 2. The working space in the cylinder' 2 is surrounded by anannular space 3 which com- .municates, through an annular passage 4',with the working space inside the cylinder 2. At the top of the head thelid 5 has introduced through it a plurality of tubular heating elements6 which form, so-to-say, re-entrant parts in the space 3. Forsimplicity's sake the figure only shows two of these tubes 6; Under thetubes 6 is arranged a regenerator 1. When .the displacer I moves upwardsthe medium enclosed in the working space 2 is driven upwards and entersthrough the passage 4 into the annular space 3,

the medium flowing between the tubes 6. The

latter are flattened and are closed at their bottom ends 8 and open attheir top ends 9. In the longitudinal direction they are divided intotwo parts by partitions i0 (shown in Figure 1 by dotted lines inhorizontal cross section in Figure 7) ,which nearly extend to the bottom8 of the tubes.

This is shown more clearly in the longitudinal sectional view of Figure8. In this manner a U- shaped duct is formed in the re-entrant parts.

' designates the lid of the engine.

view taken along the line IV-IV of Figure 2 as noted hereinabove,reference numeral 2| desi nates the cylinder lining in which a displacer(not shown) is movable. Reference numeral 22 Outside the cylinder lining2| is provided an annular chamber 4|, which is externally circumscribedby a wall 33. This chamber comprises spaces or ducts 42 for the mediumwhich is active in the engine, and spaces or ducts 43 for the mediumwhich is in heat-exchanging contact with the former. These ducts areseparated from one another by the zigza screen 24. This screen has, atthe top and at the bottom. a folded rim 25 which is secured, by means ofsoldered or welded joints to the adjacent parts ofthe engine. The topends of the ducts 42 intended for the working medium are closed by theelongated projecting parts 4'4 of the lid 22 of the engine and thebottom ends of the ducts for the gases which are in heat-exchangingcontact with the working medium, for example, the flue gases of a burnerare closed by means of the elongated projecting parts of a plate 23. Thetop ends of the ducts .43 are open. Into these the flue gases of theFig. 9 is a horizontal cross section of an alternate construction of thetube 6 wherein a rectangularly shaped heating element 6' is showninstead of the circular tube 6. In the rectangularly shaped heatingelement 6, i0 is the dividing partition and I4 designates the ribs.Adjacent the top of the tubes 6 is an annular parti- F tion H, by meansof which the inlet apertures l2 of the tubes 6 are separated from theiroutlet apertures l3. On top of the head of the engine, inside theannular partition II, is arranged a burner whose exhaust gases can thusonly flow through the U-shaped ducts in the tubes 6. These gases followthe path designated by arrows. The working medium flowing between thetubes 6 is consequently heated by the walls of these tubes. Owing to thefact that a great number of ribs H are provided on the outside of thereentrant parts, the latter have a great number of ducts formed on themby which the working medium is subdivided to a greater extent and bywhich all these parallel-flows of the working medium come into intimate,heat-exchanging contact with the walls of the tubes 6. It can be seenfrom Figure 1 that by the inclined position of the ribs I4 with respectto the longitudinal axis of the walls of tubes 6 the ducts existingbetween these ribs are short with the result that the resistanceexperienced by the working medium is low. The longitudinal axis of there-entrant parts 6 may be positioned in parallel with the axis XX of theworking space, or. as is the case and the annular'partition 32. Thecombustion gases traverse the spaces intended for them in the zigzagscreen and leave at 34 from the heatexchanger. The path of the fluegases is designated by arrows P. The working medium, the course of whichin the heat-exchanger is designated by arrows Q, flows past the top edgeof the cylinder lining 2| into the spaces of the zigzag screen, whichare open to the inside, traverses these spaces and leaves theheat-exchanger through the apertures between the projecting parts 23.Subsequently, this medium finds its way to the regenerator 21, which isenclosed between the outer wall of the engine and the wall 29. In orderto reduce the clearance space in the engine, the space 30 in the engineis separated from the space for the working medium by means of theaforesaid wall 29 and the wall 28, which is provided with embossed parts45. As can be. seen from the figures, the walls of the screen arefurnished with ribs 26, which are preferably provided in them bypressing before the screen has been folded zigzag. As can moreparticularly be seen from Figure '2, these ribs form an angle of about45 with the longitudinal direction (which extends parallel with the axisXX of the engine space) of the wall, which is formed in this case by thezigzag screen 24. It is thus ensured that the paths thus produced alongthe screen for the working medium in the engine have a directionsomewhat corresponding to the shortest path of the working medium fromthe engine space to the regenerator and conversely. Short gas paths arethus ensured, which is of importance for a minimum resistance of thegas, whilst the ribs ensure a particular satisfactory heatexchangingcontact between the two media.

Owing to .the fact that the ribs 26 have been obtained by pressing thematerial of the screen 24, in this form of construction the paths forthe flue gases also have ribs. due to which the flue gases along theribs follow paths which are substantially parallel to the paths for theworking medium and which consequently form also an angle of 45 with thelongitudinal direction of the parts of the zgzag wall 24. The spacesintended for the flue gases contain screens 3| of key-shaped sectionswhich, on the one hand. prevent the walls of the zigzag screen frombeing bent outwards due to any difference of pressure which may existbetween the spaces on either side of these walls while, on the otherhand, the flue gases are thus compelled to flow along the ribs providedon the walls of the screen 24. The spaces inside the screens 3! areclosed at their top by the partition 32. It can furthermore be seen fromFigure 2 that the connecting lines DD and EE between the extreme pointsof the ribs 26 make an angle with the axis X--X of the working space. Itis'thus ensured that the medium flowin from the working space to theregenerator or from the regenerator to the working space (arrows Q) andthe combustion gases arrows P) are distributed somewhat evenly over theducts between the ribs 26.

Figures 5 and 6 are partial longitudinal and cross sectional Viewsrespectively of a third form of construction of the heat-exchanger inthe engine according to the invention. In this case the working space 50of the engine is surrounded by an annular space 5! which comprises ducts53 for the working medium and ducts 54 for the medium which is inheat-exchanging contact with the former. In the ducts 56 are providedpipes 55, which contain a combustible gas. These pipes have outlets 56through that part of their length which protrudes into the space 54.'Besides, the partitions 51 between the spaces 53. which extendsubstantiall radially, are provided with ribs 58. When theheat-exchanger is operative and the gases at the outlets 56 are burninsWe obtain, by suitably shaping the mouthpieces of the burners, theflames 59 which are shown in Figure 6. They transfer their heat to theribs 58 on the walls 51, whereas the ribs provided on the other side ofthewalls 5'! transfer this heat in their turn to the working medium inthe engine space. Consequently, in this form of construction there areribs on either side of the walls 51, which ribs make an angle with thelongitudinal direction of the walls, which extends in parallel with theaxis Y-Y of the working space.

What I claim is:

1. A caloric piston machine comprising first means defining a workingchamber for the working medium used in the machine, second meansdefining an annular chamber surrounding a section of said workingchamber, said Working chamber and said annular chamber being in gascommunication with each other whereby the working medium may flowbetween said working chamber and said annular chamber, at least one heatexchanger element in said annular chamber, said heat exchanger elementhaving a heat exchanging fluid inlet and a heat exchanging fluid outletand comprising wall means for keeping the working medium separated fromthe heat exchanger fluid but in heat exchange relationship therewiththrough the body of said wall means, said heat exchanger elementextending longitudinally in said annular chamber substanchamber, andsaid wall means of said heat exchanger element having a plurality ofparallel projections thereon which are at an angle to the longitudinalaxis of said heat exchanger element.

2. A caloric piston machine as claimed in claim 1. wherein the heatexchange element is in the form of a tube protruding into the annularchamber.

3. A caloric piston machine comprising first means defining a workingchamber for the working medium used in the machine, second meansdefining an annular chamber surrounding a sec tion of said workingchamber, said working chamber and said annular chamber being in gascommunication with each other whereby the working medium may flowbetween said working chamber and said annular chamber, at least one heatexchanger element in said annular chamber, said heat exchanger elementhaving a heat exchanging fluid inlet and a heat exchanging fluid outletand comprising wall means for keeping the working medium separated fromthe heat exchanger fluid but in heat exchange relationship therewiththrough the body of said wall means, said wall means being in the formof a tube, said tube extending longitudinally in said annular chamberand slightly inclined in relation to the axis of said working chamber,and said tube having a plurality of parallel projections thereon whichare at an angle to the longitudinal axis of said tube in said annularchamber, said angle being in a direction opposite the inclination ofsaid tube.

4. A' caloric piston machine as claimed in claim 1, wherein the wallmeans comprises a zigzag screen.

5. A caloric piston machine as claimed in claim 1, wherein the parallelprojections are ribs pressed from the wall means.

6. A caloric piston machine comprising first means defining a workingchamber for the working medium used in the machine, second meansdefining an annular chamber surrounding a section of said workingchamber, said working chamber and said annular chamber being in gascommunication with each other whereby the working medium may flowbetween said working chamber and said annular chamber, at least one heatexchanger element in said annular chamber, said heat exchanger elementhaving a heat exchanging fluid inlet and a heat exchanging fluid outletand comprising wall means for keeping the working medium separated fromthe heat exchanger fluid but in heat exchange relationship therewiththrough the body of said wall means, said heat exchanger elementextending longitudinally in said annular chamber substantially in thedirection of the axis of said working chamber, and said wall means ofsaid heat exchanger element having a plurality of parallel projectionsthereon which are at an angle to the longitudinal axis of said heatexchanger element, said wall means comprising a zigzag screen and havingspacer elements in the spaces formed by said zigzag screen.

7. A caloric piston machine comprising first means defining a workingchamber for the working medium used in the machine, second meansdeflning'an annular chamber surrounding a section of said workingchamber, said working chamber and said annular chamber being in gascommunication with each other whereby the working medium may flowbetween said working chamber and said annular chamber, at least one heatexchanger element in said annular chamber, said heat exchanger elementhaving a heat exchanging fluid inlet and a heat exchanging fluid outletand comprising wall means for keeping the working medium separated fromthe heat exchanger fluid but in heat exchange relationship a combustiblegas projecting thereinto and ending therein with a plurality ofapertures, the projections on the sides of said wall means which facesaid supply pipe being located in relation to said apertures so as toform ducts on said wall means for the flames coming out of saidapertures.

GERARD JAN HUBERTUS VERMEER.

REFERENCES CITED Thefollowing references are of record in the file ofthis patent? UNITED STATES PATENTS Name Date Lundgaard Apr. 21, 1925Number

